Exhalation device for breathing mask

ABSTRACT

An exhalation device for a respiratory mask comprises a valve member which is biased toward its seat by its own resiliency and by additional spring means which may optionally be rendered inoperative by a releasing mechanism. The mechanism comprises a manually actuatable member such as a control ring, knob or lever movable on the canister of the device to a position where a flexible cord connected to the member exerts on the additional spring a force which prevents it from acting on the valve member.

United States Patent Inventor Paul Ulmann BagnoIs-sur-Ceze, France Appl. No. 839,243 Filed July 7, 1969 Patented Apr. 20, 1971 Assignee Commissariat A LEnergie Atomique Paris, France Priority July 11, 1968 France 158,752

EXHALATION DEVICE FOR BREATHING MASK 6 Claims, 9 Drawing Figs.

US. Cl 137/529, 128/ 146.4

Int. Cl A62b 23/02 Field of Search 128/1465, 146.4, 142.3, 703; 137/529, 635.3; 138/45, 46; 360/(lnquired) [5 6] References Cited UNITED STATES PATENTS 1,349,335 8/1920 Gammeter 137/529(X) 3,474,783 10/1969 Ulmann 128/1423 FOREIGN PATENTS 705,216 3/1954 Great Britain 137/529 Primary Examiner-Richard A. Gaudet Assistant Examiner-G. F. Dunne Attorney-Cameron, Kerkam and Sutton PATENTED M20197! 3575206 SHEET 10F 3 FIG. I

FIG. 2

FIG. 3

PATENTEUAPR2 0 mn SHEET 2 0F 3 FIG. 7'

FIG. 4

FIG. 5

PATENTEDAPRZOWI 3575205 sum 3 OF 3 IEXIIIALATIGN DEVICE FOR BREATIIWG MASK The present invention is directed to an exhalation device for a breathing mask in which the exhaled air is discharged through an outlet valve as soon as the pressure within the mask exceeds the pressure of the surrounding atmosphere by a predetermined difference. Two types of breathing masks are in common use. In one type, which will be referred to hereinafter as an isolating mask, the facepiece is supplied with a breathing mixture at a pressure which is distinctly higher than that of the surrounding atmosphere (the overpressure being usually between 20 and 50 mm. H O) in order to prevent the penetration of toxic gases or dust particles from the atmosphere through the facepiece at any locations in which leaktightness is faulty. In the second type of breathing mask, or so-called filtering mask, the facepiece is supplied from the surrounding atmosphere through a filter cartridge and an inlet valve which opens under the action of the partial vacuum which is developed within the mask as a result of inhalation by the wearer.

For reasons of safety and adaptability, an operator is sometimes obliged to make use of a filtering" mask under certain environmental conditions and of an isolating" mask under different conditions, However, in the case of operation as an isolating mask, the exhalation device must be calibrated in order to remain closed as long as the pressure within the interior of the mask does not exceed atmospheric pressure by a few millimeters of water in addition to the supply overpressure. If the same calibration is maintained during operation as a filtering mask, considerable respiratory discomfort is consequently experienced by the wearer.

This problem is solved by means of the exhalation device which is described in US. Pat. application Ser. No. 612,974, filed Jan. 3l, I967, now US. Pat. No. 3,474,783. This device comprises a canister fitted with a valve seat for connecting the interior of the mask to the atmosphere, a valve which is elastically applied against the valve seat with slight pressure, elastic means adapted to cooperate with the valve so as to exert thereon an additional force which tends to apply said valve against its seat and which is of sufiicient intensity to balance the supply overpressure during operating in the isolating condition as well as a mechanism for effecting the positive release of said elastic means.

The chief aim of the invention is to provide an exhalation device which meets practical requirements with even greater effectiveness than the device mentioned above, particularly insofar as it achieves enhanced dynamic operation and virtually removes any danger of jamming of the expiratory valve.

To this end, the invention proposes an exhalation device comprising a canister provided with a valve seat for connecting the interior of the mask to the surrounding atmosphere, a valve which is elastically applied against said valve seat, elastic means adapted to cooperate with said valve in order to exert thereon an additional force which tends to apply said valve against its seat and a releasing mechanism, said device being especially characterized in that the releasing mechanism comprises a member which is displaceable by hand and by means of a flexible cord secured to said elastic means at one extremity thereof and securedat the other extremity to said member which is displaceable between a position in which said elastic means are free and a position in which the cord exerts on said means a tractive force which maintains them in a position of disengagement with respect to the valve.

A better understanding of the invention will be gained from the following description of particular embodiments which are given by way of nonlimitative example, reference being made to the accompanying drawings, in which:

FIG. 1 is a sectional view taken on a plane which passes through the axis (plane H of FIG. 2) of a device in accordance with a first embodiment of the invention, the components being shown in the position occupied for the purpose of operation as a filtering" mask;

FIG. 2 is a sectional view taken along line ll-ll of FIG. I, a part of the components having been removed in the left-hand portion of the FIG. in order to expose the valve seat;

FIG. 3, which is similar to a portion of FIG. 2, shows the components in the position occupied for the purpose of operation as a filtering mask;

FIG. 4 is an axial sectional view of a second embodiment of the invention, the components being shown in the position occupied at the time of operation as an isolating mask;

FIG. 5 shows the top portion of the device according to FIG. 4, the components being shown in the positions occupied at the time of operation as a filtering mask;

FIG. 6 is a top view showing a detail of the mechanism for releasing the device of FIGS. 4 and 5;

FIG. 7 is an axial sectional view of a device according to a third embodiment of the invention, the. components being shown in the positions occupied at the time of operation as an isolating mask; I

FIG. 8 is an axial sectional view of the top portion of a fourth embodiment of the invention; and

FIG. 9 is a top view of FIG. d.

The device which is illustrated in FIGS. 1 to 3 comprises a canister which is formed by a tubular cylindrical body 10 and a cover T6. The body 10 is intended to be joined in leaktight manner to the skirt of a facepiece (not shown). The outer face in the radial direction of a flange of the body 10 is provided with a groove 12 in which an internal annular boss of the cover I6 is fixed by snap-on engagement. The body has an annular surface which constitutes the seat 18 of an elastic expiratory valve 20 having a mushroom shape. The valve stem 22 is fixed in a support which is visible in FIG. 1 and in the left-hand portion of FIG. 2. Said support is constituted by a central hub 24 which is joined to the body It) by means of four arms 28 having an elongated profile in the direction of flow. There is placed between the expiratory valve and the mask a screen 30 which has a mesh of the order of l millimeter, for example, and which is retained between the hub 24 and an enlarged portion of the valve stem 22.

The cover 16 has a cylindrical portion and a convex end wall in which are drilled holes 1.5 mm. in diameter, for example. At a level corresponding to two-thirds of its height, the cover 16 is pierced by 10 rectangular windows 31 protected by a grid 32 which surrounds the cover. The top or end wall of the cover is provided with a central internal projection MI in which is pierced an elbowed duct which serves as a motiontransmission means for a traction thread or cord 36, the function of which will become apparent hereinafter. There is also formed in the internal face of the end wall a support 37 which is intended to serve as a seat for an overpressure spring 38.

When the expiratory valve 20 is in position and is not subjected to any pressure force, said valve is in the position shown in FIG. I in full lines, The edge of said valve is thus applied against the valve seat 18 and forms a separation between the interior of the breathing mask and the surrounding atmosphere. When an overpressure with respect to the atmosphere and even a low overpressure is developed within the breathing mask, the expiratory valve is accordingly bent back towards the position shown in chain-dotted lines: this is the case of exhalation during operation as a filtering" mask.

Elastic means are provided for the purpose of cooperating with the valve 20 and exerting on this latter an additional force which tends to apply said valve against its seat at the time of operation in the isolating" condition. These means comprise a cup Ml and a spring 38. The cup 40 consists of a ring having a diameter which is smaller than that of the cover and on the rim of which are formed eight semicircular centering projections 42, said ring being joined by means of eight radial arms 44 to a convex central hub. Thus, the exhaled air follows the path indicated by the arrows F. That side of the cup 40 which is in oppositely facing relation to the valve 20 closely conforms to the shape of this latter in the inoperative position. The top face of the ring which is provided with a groove 46 serves as a seat for the overpressure spring 38.

The mechanism for releasing the elastic means comprises the control cord or thread 36 and a control ring 48 provided with an operating lug 50 (as shown in FIG. 2). Said ring is capable of rotating on the top portion of the cover corresponding to one-third of the height of this latter and is provided on its internal face with three male lugs 52 which are intended to slide within three grooves formed in a circular arc in the outer face of the top third of the cover 16. Said lugs serve to retain the ring 48 in the cover and permit the rotation of the ring only between two end positions shown respectively in FIGS. 2 and 3.

One of the ends of the cord 36 is attached to the hub of cup 40. The cord extends axially from the hub to the projection 34, follows the elbowed passageway which is formed within this latter, traverses the cover 16 through a flared opening 54 (as shown in FIG. 2) and extends along a bore 56 of the control ring 48. The other end of the cord is retained against the face onto which the bore 56 opens at the periphery of the ring. A circular groove 58 is formed in the internal face of the ring around the outlet of the duct in order to prevent the cord from being locked in position during operation of the ring 48. The cord is advantageously formed of polyamide material, for example ofnylon or rilsan.

The position and length of the male lugs 52 and of the corresponding grooves are such that, in one of the end positions of the control ring (FlG. 2), the cord is fully slackened and permits the cup 40 to rest on the valve in this case, the force exerted by the overpressure spring 38 is added to the force which is produced by the elasticity of the valve 20. How ever, only the valve and the cup 40 are in motion during the operation whilst the control ring 48 remains motionless. Thus, the dynamic operation of the device constitutes an improvement over the device as disclosed in Pat. application Ser. No. 612,974 filed .lan. 3l, l967 cited earlier by virtue of the lower mechanical inertia of the moving system.

The operation which has just been defined corresponds to the use of an isolating mask. In the other end orientation of the control ring 48, the cord 36 returns the cup 40 into the position shown in FIG. 1 in which the expiratory valve is capable of free displacement. This arrangement is accordingly adopted when the mask is used in the filtering condition.

A retaining mechanism (not shown) is preferably associated with the control ring in order to prevent this latter from yielding under the tractive force exerted by the spring 38 and returning to the orientation which is shown in FIG. 2. To this end, it is possible, for example, to make use of a flexible strip which is carried by the cover end wall and which is adapted to engage in a slot provided for this purpose in the ring 48. lt may also be considered sufficient to utilize the forces developed by friction between the ring and the cover in order to prevent the return movement of said ring.

Among the advantages of the device which has just been described, it is worthy of note that the cord 36 which is both an essential and delicate element is not liable to catch or fail since it is protected along its entire path. At the time of operation (both in the isolating condition and in the filtering condition of the mask), the valve does not have to actuate the control ring at the time of opening and this affords a double advantage: the dynamic response is improved; opening of the valve is not liable to be prevented as a result of jamming of the control ring. The type of operation which is provided by means of the valve is indicated in all cases by the orientation of the control lug 50.

The devices which are shown in the other FlGS. provide the same advantages. For the sake of enhanced clarity, the corresponding components of all the forms of construction illustrated are designated by the same reference numerals to which are assigned the prime and second indices.

The mechanism for releasing the device as illustrated in FIGS. 4 to 6 comprises a cord 36 which is again attached to the cup 40'. Said cord traverses the end wall of the cover 16 through a guide aperture and the other end of the cord is attached to a knob 60 which is capable of radial displacement over the external end wall face of the cover 16. The knob 60 is composed of an externally projecting control head which is intended to be actuated by hand and a dovetail section slider 62 which is slidably fitted in grooves 64 formed in the cover.

As shown in FIG. 6, one of the sides of the slider 62 is provided with a boss which is adapted to engage in either of the two cups 64 and 66 of the cover in order that the knob 60 can be locked elastically in either of its two end positions. The cup 66 is placed in such a manner as to retain the knob at the center of the cover. In this position (as shown in F IG. 4), the knob releases the cord 36 and makes it possible for the spring 38 to apply the cup 40' against the valve 20'. On the contrary, in the position of the knob which corresponds to the engagement of the boss in the cup 64, the cord 36' exerts an axial tractive force on the cup 40' and maintains this latter out of contact with the valve 20 (as shown in H05. 5 and 6).

Since the knob is located at the center of the cover at the time of operation as an isolating" mask, the operator can readily ascertain by feeling the knob whether the device is either in the isolating position or in the filtering position.

In the form of construction which is illustrated in H6. 7, the knob 60" is capable of radial displacement between two radially aligned positions which are both offcenter. The knob 60 consists of a round head with a flat underface provided with two bosses which are aligned in the radial direction. One boss of the knob is intended to engage in a cup 64" of the cover when the device is in the filtering position and the other boss is intended to engage in a cup 66" when the device is in the isolating position (as shown in FIG. 7). The head has a tailpiece extension for guiding the knob within a radial groove formed in the end wall of the cover 16". Said head is held against the cover by means of a screw 68 which traverses said cover and carries a retaining nut 70. The cord 36" is attached to the lower end of the screw 68.

ln the form of construction which is illustrated in H08. 8 and 9, the cord 36" again traverses the end wall through an axial guide aperture and the end of said cord is attached to a lever 72 which pivots about a pin 74 mounted on the cover 16". Lugs 64 and 66" carried by the end wall of the cover are capable of engaging in recesses formed for this purpose in the sides of the lever 72 (as shown in FIG. 9) so as to retain this latter in either of two positions at in which the lever is placed flatwise against the end wall These two locking orientations correspond to the filtering" position (as shown in HO. 8) and "isolating" position (as shown in chain-dotted lines in FIG. 9). Although the cord 36" passes outside the canister in this form of construction, said cord is not liable to catch or to fail inasmuch as it is protected by the projection formed by the lever 72 as it extends along this latter.

We claim:

1. An exhalation device for a respiratory mask, including a canister formed with a valve seat through which the interior of the mask is adapted to communicate with the surrounding atmosph'ere, a resilient valve member permanently biased toward said valve seat, resilient means cooperating with said valve member and exerting thereon an additional force biasing said valve member toward said seat and a releasing mechanism, said releasing mechanism comprising a manually actuatable member movable on said canister between a first position and a second position and a flexible cord having one end cooperating with said resilient means and its other end secured to said manually actuatable member, said first and second position of said manually actuatable member so selected that the flexible cord releases said resilient member when said manually actuatable member is in one of said positions and exerts a pulling force on said resilient means which prevents it from acting on the valve member when said manually actuatable member is in the other position.

2. An exhalation device according to claim 1, wherein said resilient means comprises a spring compressed between a bottom wall of said canister and a cup movable toward and away from the valve member and wherein said one end of the cord is secured to a central portion of the cup.

3. A device according to claim 2, wherein said canister in formed with guiding means constructed and arranged for guiding the cord axially toward the cup with respect to movement thereof.

is connected to the knob at the end thereof.

6. A device according to claim 3, wherein said manually actuatable member consists of a lever pivotably mounted on the bottom wall of the canister for 180 rotation from said first to said second position, and wherein said cordtraverses the bottom wall of the canister and is connected to an intermediary point of the lever. 

1. An exhalation device for a respiratory mask, including a canister formed with a valve seat through which the interior of the mask is adapted to communicate with the surrounding atmosphere, a resilient valve member permanently biased toward said valve seat, resilient means cooperating with said valve member and exerting thereon an additional force biasing said valve member toward said seat and a releasing mechanism, said releasing mechanism comprising a manually actuatable member movable on said canister between a first position and a second position and a flexible cord having one end cooperating with said resilient means and its other end secured to said manually actuatable member, said first and second position of said manually actuatable member so selected that the flexible cord releases said resilient member when said manually actuatable member is in one of said positions and exerts a pulling force on said resilient means which prevents it from acting on the valve member when said manually actuatable member is in the other position.
 2. An exhalation device according to claim 1, wherein said resilient means comprises a spring compressed between a bottom wall of said canister and a cup movable toward and away from the valve member and wherein said one end of the cord is secured to a central portion of the cup.
 3. A device according to claim 2, wherein said canister is formed with guiding means constructed and arranged for guiding the cord axially toward the cup with respect to movement thereof.
 4. A device according to claim 3, wherein said manually actuatable member consists of a control ring rotatably mounted on the canister and wherein said canister is formed with a passage (so located as to guide the cord radially of said canister between said passage and said guiding means.
 5. A device according to claim 3, wherein said manually actuatable member consists of a knob slidably mounted on the bottom wall of the canister between said first and second positions and in which said cord projects through said end wall and is connected to the knob at the end thereof.
 6. A device according to claim 3, wherein said manually actuatable member consists of a lever pivotably mounted on the bottom wall of the canister for 180* rotation from said first to said second position, and wherein said cord traverses the bottom wall of the canister and is connected to an intermediary point of the lever. 